Enumerates converting user prior engagement types and lifetime-value bucket

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/enums/converting_user_prior_engagement_type_and_ltv_bucket.proto)

| Enums ||
|---|---|
| ## `NEW` | Converting user is new to the advertiser. |
| ## `NEW_AND_HIGH_LTV` | Converting user is new to the advertiser and has high lifetime value. |
| ## `RETURNING` | Converting user is returning to the advertiser. Definition of returning differs among conversion types, such as a second store visit versus a second online purchase. |
| ## `UNKNOWN` | The value is unknown in this version. |
| ## `UNSPECIFIED` | Not specified. |